Even though playing online slots can result in large financial gains, it's important for players to use caution when playing and understand the risks involved when using real money to gamble. A safe and esattaking.upnjoyable experience requires a proper understanding of game mechanics, odds, and responsible gambling practices. Select Games with High RTP Calculations. One way to increase your chances of winning big when playing real money online slots is to select games with high return-to-player (RTP) percentages. The amount of money that a slot machine returns to players over time is indicated by the RTP percentage.